This invention pertains to membranes and diaphragms suitable for the electrolytic production of a halogen and alkali metal hydroxide and more in particular to a method to fabricate such membranes and diaphragms by bonding polymeric materials together.
Gaseous halogens, such as chlorine, have been produced from alkali halides, for example sodium chloride, in electrolytic cells with an anode and cathode positioned within suitable compartments spaced apart by ion and liquid permeable asbestos diaphragms. More recently, attempts have been made to replace the asbestos diaphragm by either ion permeable and liquid impermeable polymeric ion exchange membranes or by ion and liquid permeable polymeric diaphragms. In any of such cells, a gaseous halogen is released at the anode and an aqueous solution of an alkali metal hydroxide is formed in the cathode compartment.
Oftentimes the polymeric membranes or diaphragms have unacceptably short life spans in the electrolytic cells because of leaks occurring at seams in the polymeric material permitting unacceptable quantities of electrolyte to flow from the anode compartment to the cathode compartment or vice versa. Such flow of electrolyte can reduce the efficiency of the electrolytic cell sufficiently to make it uneconomical to operate. It is, therefore, desired to provide a method to fabricate a polymeric membrane or diaphragm in such a manner to provide a membrane or diaphragm which is substantially leak-free at any seams, or joints, in the polymeric material.